This topic presented the relationship between physicochemical parameters and waterbirds assembling at Garaet Hadj Tahar (occidental Numidia, northeast of Algeria). Our data were collected from January 2018 to December 2018. Five physical parameters and four nutrient parameters, were measured at this wetland. We have noted 35 waterbirds species belonging to eleven family. All waterbirds of this wetland listed as least concern according to IUCN red list, except the three Anatidae key species with a conservation statuts: Aythya nyroca (near threatned), Oxyura leucocephala (endangered species) and Marmaronetta angustirostris (vulnerable). The maximum values of abundance, species richness, Shannon diversity index and Simpson diversity index were noted in wintering period but not for the Pielou‟s evenness index. Only five physicochemical parameters influenced the waterbirds population assembling at this wetland. Garaet Hadj Tahar wetland must getting more conservation interest and surveys in order to maintain the biodiversity of this hotspot wetland.